package doubleLinkedList;

public interface IDoubleLinkedListOperation {
    //头插
    boolean addFirst(int val);
    //尾插
    boolean addLast(int val);
    //头删
    boolean removeFirst();
    //尾删
    boolean removeLast();
    //链表长度
    int size();
    //查看是否包含key
    boolean contains(int key);
    //清除链表
    void clear();
}
